When the officers of the law seized the safe and opened it, they found there what Arsène Lupin had left⁠—nothing.

Such are the facts; and I learned the sequel to them, one day, when Arsène Lupin was in a confidential mood. He was pacing to and fro in my room, with a nervous step and a feverish eye that were unusual to him.

“After all,” I said to him, “it was your most successful venture.”

Without making a direct reply, he said:

“There are some impenetrable secrets connected with that affair; some obscure points that escape my comprehension. For instance: What caused their flight? Why did they not take advantage of the help I unconsciously gave them? It would have been so simple to say: ‘The hundred millions were in the safe. They are no longer there, because they have been stolen.’ ”

“They lost their nerve.”